New PECL extesnion: mysqlnd_krb

Hello!

I am from MySQL Connectors Team and we would like to publish a new PECL 
extension named `mysqlnd_krb`. This extension would provide ability for 
`mysqlnd` to login to MySQL server accounts that use Kerberos 
authentication [1].

Our Release Engineering team already has a PECL account 
`[email protected]` and I think it can be used to create and maintain the 
new extension. In general the new extension should be handled similar to 
`mysql_xdevapi` extension that we developed and maintained earlier [2]. 
In particular we would like the source code to appear at 
github.com/php/pecl-database-mysqlnd_krb, similar to how it is arranged 
for `mysql_xdevapi` extension [3].

Regards,
Rafal


[1] 
https://dev.mysql.com/doc/refman/8.0/en/kerberos-pluggable-authentication.html
[2] https://pecl.php.net/package/mysql_xdevapi
[3] https://github.com/php/pecl-database-mysql_xdevapi